1. Field of the Invention
The present invention relates to an actuator and particularly a manufacturing method of an actuator for ink jet printer head.
2. Description of the Prior Art
An ink jet printer head actuator using a piezoelectric substance is usually composed of an infrastructure made of vibration plate and chamber, a piezoelectric/electrostrictive film which undergoes mechanical deformation if electricity is applied as the film is fixed on vibration plate, and electrodes which transmit electricity to the piezoelectric/electrostrictive film.
Piezoelectric body of actuator has characteristics poling when electricity is applied. If electricity is supplied to upper and lower electrodes formed on and under piezoelectric substance under poling state, piezoelectric body located between electrodes undergoes mechanical deformation or vibrates with recycling of deformation and restoration.
In ink jet printer head, ink is jetted to the recording medium as vibration plate undergoes mechanical deformation thicknesswise if the piezoelectric substance of actuator vibrates.
Thus in ink jet printer head, infrastructure composed of chamber and vibration plate is an important factor for actuator operation.
In order to form actuator infrastructure using an electrostrictive substance, ordinarily chamber and vibration plate are formed mainly by half etching of wet etching process in case where metal is used as the material while three dimensional structure body is formed by sintering and pressing of a vibration sheet and a sheet of punching method in case where ceramic is used as the material.
But it is difficult to obtain vibration plate of wanted thickness by controlling the etching speed and time in case where actuator infrastructure is formed by half etching of metal while there is problem that precision and yield ratio are lowered at the processing step in case where actuator infrastructure is formed by ceramic punching and sinter-pressing.
Purpose of the present invention to solve the above problems is to provide a manufacturing method of actuator for ink jet printer head by bonding the chamber plate and the vibration plate composed of silicic material according to the direct silicon bonding.
The present invention to achieve the above purpose relates to a manufacturing method of actuator for ink jet printer head comprising steps of: providing a silicon wafer; forming an etching stop layer on bottom side of the silicon wafer; forming a vibration plate made of silicic material; bonding the vibration plate onto bottom side of the etching stop layer by way of heat treatment; forming a chamber plate made of silicic material; forming a chamber on the chamber plate by way of full etching of the chamber plate; bonding the chamber plate where the chamber is formed, onto bottom side of the vibration plate by way of heat treatment; completing an actuator infrastructure by removing the silicon wafer; forming a lower electrode on the infrastructure; forming a piezoelectric/electrostrictive film which actuates when electrified, in a definite pattern upon the lower electrode; and forming an upper electrode upon the piezoelectric/electrostrictive film.
Also the present invention relates to a manufacturing method of actuator for ink jet printer head comprising steps of : providing a silicon wafer; forming an etching stop layer on bottom side of the silicon wafer; forming a vibration plate made of silicic material; bonding the vibration plate onto bottom side of the etching stop layer by way of heat treatment; forming a chamber plate made of silicic material; forming a chamber on the chamber plate by way of etching of the chamber plate; forming a channel in lower part of the chamber by etching the chamber plate remaining at lower part of the chamber; bonding the chamber plate where the chamber and the channel are formed, onto bottom side of the vibration plate by way of heat treatment; completing an actuator infrastructure by removing the silicon wafer; forming a lower electrode on the infrastructure; forming a piezoelectric/electrostrictive film which actuates when electrified, in a definite pattern upon the lower electrode; and forming an upper electrode upon the piezoelectric/electrostrictive film.